Planetariums and Science Centers

Planetariums, museums, and science centers can be found in most major cities around the world. Science centers are an outgrowth of the original planetarium theaters, which, at their inception in the 1930s, were the only places the general public could learn about science in general and astronomy in particular.

A planetarium consists of a hemispherical-domed theater in which a specialized star projector can display the night sky at any time of the year. Central to the experience is the planetarium projector. There are two principle types of star projectors: opto-mechanical and digital.

Traditional Planetarium Projectors

Opto-mechanical planetarium projectors typically have two spheres incorporating carefully drilled metal plates that, when illuminated, reproduce the constellation patterns on the reflective dome surface. In addition, the positions of planets hundreds of years into the past or future can be displayed. There are four principle manufacturers of this kind of projector: Zeiss (Germany), Minolta (Japan), Gotoh (Japan), and Spitz, Inc. (United States). Walther Bauersfeld of the Zeiss company built the first opto-mechanical star projector in 1923.

Digital Planetarium Projectors

A digital projector called "Digistar®," short for digital stars, was introduced in 1980 by Evans and Sutherland, Inc. Because of its low profile, the projector is effectively hidden in the center of the theater. Digistar® is built around a cathode-ray tube with a large fish-eye lens. A computer database of 9,000 stars can be projected onto the dome. Since the system is computer-based, it can recreate the night sky as seen from other nearby stars in addition to the view from Earth. Constellations can be "flown around," and the solar system becomes a dynamic projection that can be rotated as if the audience were in space. The system can also be used to draw any three-dimensional object as a "wire-frame," such as an architectural model, a mathematical shape, or a spacecraft.

The Spread of Planetariums

Since the invention of the planetarium projector, many major cities have built planetarium theaters. The first theaters were built in Vienna, Rome, and Moscow, all prior to 1930. The first planetarium in the United States was the Adler Planetarium in Chicago, which opened in 1930.

During the late 1960s and early 1970s many new planetariums were built. Installations in schools and colleges were encouraged by the introduction of cheaper star projectors by Spitz, based in Pennsylvania. This expansion reflected a growth in the teaching of science during a time of great exploration of space, which culminated in humans landing on the Moon in 1969.

Evolution of Science Centers

As an outgrowth of the tremendous interest in science generated by planetariums, and responding to a greater public desire to learn more, the concept of a science center developed. Science centers provide hands-on activities that engage people in science. Some science centers combine locally built exhibits that match local interests with traveling exhibits that focus on particular issues or subjects, such as "Missions to Mars" or "Global Warming." Science centers develop their own educational programs. Today, most cities have a science center or a planetarium. People working in various departments, such as education, marketing, technical support, administration and presentations, staff these large informal science learning centers. The larger science centers often incorporate a large-format film theater in addition to the popular planetarium theaters.

Planetariums of the Twenty-First Century

Planetarium theaters come in many shapes and sizes. Some serve as unique classrooms and belong to schools or colleges. Classes held in planetariums teach the basics of astronomy, the night sky, the seasons, and other topics related to the science curriculum. Larger theaters, such as the Adler Planetarium in Chicago, are stand-alone facilities. Others are part of larger science centers. For example, the Buhl Planetarium is part of the Carnegie Science Center in Pittsburgh, Pennsylvania. These larger facilities play to a general public audience, and their goals are very different from school-based theaters. They encourage the spark that may ignite a child's interest in science, and strive to develop public's understanding of space and astronomy.

At the dawn of the twenty-first century, traditional planetarium projectors are being replaced with modern digital projectors. Planetariums are changing from places to view the night sky as seen from Earth, into amazing domed theaters where audiences are immersed in three-dimensional digital images and can be transported to a new universe full of realism. Elaborate productions using synchronized sound and narration elevate the planetarium theater to new heights. The changes have been reflected in the role of the audiences. Previously, passive audiences watched a show from beneath the dome as if in a glorified lecture theater. Now, audiences are transported to places they previously could imagine only in their dreams. Faster and more powerful computers and real-time image generation have added new capabilities to the modern planetarium theater, allowing audience interaction and making the visitor an integral part of the show.

A modern planetarium theater combines full-color video-graphics with stars. Recent advances in video technology allow full-dome, full-motion video scenes to be created. The most modern advance consists of a real-time image generator that creates images that can fill the whole dome, and five-button keypads at each seat that allow the audience to control part of the show, meaning that audience members are no longer passive participants in the immersive experience. The first two facilities in the world to house this system were Adler Planetarium in Chicago and the Boeing Cyber Dome at Exploration Place in Wichita, Kansas.

Career Options

The options for a career in the planetarium and science center industry are wide and varied. Staffing requirements include educators, scientists, computer graphic artists, teachers, exhibit designers, writers, marketing staff, and administrators.

International Planetarium Society

The International Planetarium Society, founded in 1970, is the organization for planetarium professionals. Representatives from regional planetarium associations from around the world form its council, and biennial conferences provide opportunities for exchanging ideas and experiences.

Association of Science and Technology Centers

Founded in 1973, the Association of Science and Technology Centers now numbers more than 550 members in forty countries. Members include not only science and technology centers and science museums but also nature centers, aquariums, planetariums, zoos, botanical gardens, space theaters, and natural history and children's museums.

see also Astronomy, Kinds of (volume 2); Careers in astronomy (volume 2); Careers in Space Science (volume 2).

Martin Ratcliffe

Bibliography

Wilson, Kenneth, ed. So You Want to Build a Planetarium. Rochester, NY: International Planetarium Society, 1994. Also available at <http://www.ibiblio.org/ips/sywtbap3.html>.

Internet Resources

Association of Science and Technology Centers Page. <http://www.astc.org/>.

Chartrand, Mark R. "A Fifty Year Anniversary of a Two Thousand Year Dream."The Planetarian. September 1973. <http://www.griffithobs.org/IPSDream.html>. International Planetarium Society Page. <http://www.ips-planetarium.org/>.